package com.filter;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;


public class LoginFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletResponse resp = (HttpServletResponse) servletResponse;
        HttpServletRequest req = (HttpServletRequest) servletRequest;
        Object session = req.getSession().getAttribute("USER_IN_SESSION");
        if (session == null) {
            req.setAttribute("notLogin", "请从新登录");
            req.getRequestDispatcher("/login.jsp").forward(req, resp);
            return;
        }
        //不为空则放行
        filterChain.doFilter(req, resp);
    }

    @Override
    public void destroy() {
    }
}
